/*
 * USB Serial Converter Bus specific functions
 *
 * Copyright (C) 2002 Greg Kroah-Hartman (greg@kroah.com)
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License version
 *      2 as published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>

static int usb_serial_device_match (struct device *dev, struct device_driver *drv)
{
        struct usb_serial_driver *driver;
        const struct usb_serial_port *port;

        /*
         * drivers are already assigned to ports in serial_probe so it's
         * a simple check here.
         */
        port = to_usb_serial_port(dev);
        if (!port)
                return 0;

        driver = to_usb_serial_driver(drv);

        if (driver == port->serial->type)
                return 1;

        return 0;
}

static ssize_t show_port_number(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct usb_serial_port *port = to_usb_serial_port(dev);

        return sprintf(buf, "%d\n", port->number - port->serial->minor);
}

static DEVICE_ATTR(port_number, S_IRUGO, show_port_number, NULL);

static int usb_serial_device_probe (struct device *dev)
{
        struct usb_serial_driver *driver;
        struct usb_serial_port *port;
        int retval = 0;
        int minor;

        port = to_usb_serial_port(dev);
        if (!port) {
                retval = -ENODEV;
                goto exit;
        }

        driver = port->serial->type;
        if (driver->port_probe) {
                if (!try_module_get(driver->driver.owner)) {
                        dev_err(dev, "module get failed, exiting\n");
                        retval = -EIO;
                        goto exit;
                }
                retval = driver->port_probe (port);
                module_put(driver->driver.owner);
                if (retval)
                        goto exit;
        }

        retval = device_create_file(dev, &dev_attr_port_number);
        if (retval)
                goto exit;

        minor = port->number;
        tty_register_device (usb_serial_tty_driver, minor, dev);
        dev_info(&port->serial->dev->dev, 
                 "%s converter now attached to ttyUSB%d\n",
                 driver->description, minor);

exit:
        return retval;
}

static int usb_serial_device_remove (struct device *dev)
{
        struct usb_serial_driver *driver;
        struct usb_serial_port *port;
        int retval = 0;
        int minor;

        port = to_usb_serial_port(dev);
        if (!port) {
                return -ENODEV;
        }

        device_remove_file(&port->dev, &dev_attr_port_number);

        driver = port->serial->type;
        if (driver->port_remove) {
                if (!try_module_get(driver->driver.owner)) {
                        dev_err(dev, "module get failed, exiting\n");
                        retval = -EIO;
                        goto exit;
                }
                retval = driver->port_remove (port);
                module_put(driver->driver.owner);
        }
exit:
        minor = port->number;
        tty_unregister_device (usb_serial_tty_driver, minor);
        dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
                 driver->description, minor);

        return retval;
}

#ifdef CONFIG_HOTPLUG
static ssize_t store_new_id(struct device_driver *driver,
                            const char *buf, size_t count)
{
        struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
        ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);

        if (retval >= 0 && usb_drv->usb_driver != NULL)
                retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
                                          &usb_drv->usb_driver->drvwrap.driver,
                                          buf, count);
        return retval;
}

static struct driver_attribute drv_attrs[] = {
        __ATTR(new_id, S_IWUSR, NULL, store_new_id),
        __ATTR_NULL,
};

static void free_dynids(struct usb_serial_driver *drv)
{
        struct usb_dynid *dynid, *n;

        spin_lock(&drv->dynids.lock);
        list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
                list_del(&dynid->node);
                kfree(dynid);
        }
        spin_unlock(&drv->dynids.lock);
}

#else
static struct driver_attribute drv_attrs[] = {
        __ATTR_NULL,
};
static inline void free_dynids(struct usb_serial_driver *drv)
{
}
#endif

struct bus_type usb_serial_bus_type = {
        .name =         "usb-serial",
        .match =        usb_serial_device_match,
        .probe =        usb_serial_device_probe,
        .remove =       usb_serial_device_remove,
        .drv_attrs =    drv_attrs,
};

int usb_serial_bus_register(struct usb_serial_driver *driver)
{
        int retval;

        driver->driver.bus = &usb_serial_bus_type;
        spin_lock_init(&driver->dynids.lock);
        INIT_LIST_HEAD(&driver->dynids.list);

        retval = driver_register(&driver->driver);

        return retval;
}

void usb_serial_bus_deregister(struct usb_serial_driver *driver)
{
        free_dynids(driver);
        driver_unregister(&driver->driver);
}